Add NonStop KLT Configuration for new platform kernel treading model.

This fix supports the new NonStop KLT threading model, including
configurations and documentation for using this model.

Fixes: fix-24175

Signed-off-by: Randall S. Becker <randall.becker@nexbridge.ca>

Reviewed-by: Neil Horman <nhorman@openssl.org>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/25016)